A natural arch, natural bridge, or rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion from the sea, rivers or weathering.
Delicate Arch in Arches National Park, Utah, United States
The Great Arch, Tabuk Province, Saudi Arabia
The Azure Window, Malta, which collapsed in 2017
Metate Arch, Devils Garden (GSENM), a very thin arch near the end of its life
A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins.
This conical hill in Salar de Arizaro, Salta, Argentina called Cono de Arita constitutes a landform.
Panorama of Great Smoky Mountains National Park showing physical features of a rolling plain, actually part of a broad valley, distant foothills, and a backdrop of the old, much weathered Appalachian mountain range
Karst tower landforms along Lijiang River, Guilin, China
